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PIC24HJ64 Datasheet

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PIC24HJ32GP302/304, <strong>PIC24HJ64</strong>GPX02/X04, AND PIC24HJ128GPX02/X04<br />

20.1 Comparator Voltage Reference<br />

20.1.1 CONFIGURING THE COMPARATOR<br />

VOLTAGE REFERENCE<br />

The voltage reference module is controlled through the<br />

CVRCON register (Register 20-2). The comparator<br />

voltage reference provides two ranges of output<br />

voltage, each with 16 distinct levels. The range to be<br />

used is selected by the CVRR bit (CVRCON). The<br />

primary difference between the ranges is the size of the<br />

steps selected by the CVREF Selection bits<br />

(CVR3:CVR0), with one range offering finer resolution.<br />

The comparator reference supply voltage can come<br />

from either VDD and VSS, or the external VREF+ and<br />

VREF-. The voltage source is selected by the CVRSS<br />

bit (CVRCON).<br />

The settling time of the comparator voltage reference<br />

must be considered when changing the CVREF<br />

output.<br />

FIGURE 20-2:<br />

COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM<br />

VREF+<br />

CVRSS = 1<br />

AVDD<br />

CVRSS = 0<br />

8R<br />

CVR3:CVR0<br />

CVREN<br />

R<br />

R<br />

R<br />

16 Steps<br />

R<br />

R<br />

16-to-1 MUX<br />

CVREF<br />

R<br />

R<br />

CVRR<br />

VREF-<br />

CVRSS = 1<br />

8R<br />

CVRSS = 0<br />

AVSS<br />

DS70293B-page 228 Preliminary © 2008 Microchip Technology Inc.

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